Water filtration systems for removing iron, sulphur, manganese and other contaminants and sediments from water have long been in use. Dissolved iron can discolour water due to oxidation and can thereby cause stains on contact surfaces of bathtubs and sinks or on clothing being washed. Sulphur tends to have an unpleasant odour. Water that has been filtered of these contaminants is more pleasant to drink, cook and wash with, and otherwise use.
Filtration systems are often positioned near to where water enters a home, office, or industrial building from an external source, such as a well or municipal water distribution system, so that the water can be filtered of the contaminants prior to any water softening and further distribution and use. Such systems typically comprise a water tank storing a filtration media and a control system for switching between a service mode and a regeneration mode.
During service mode, water entering the filtration system is caused to pass through the filtration media within the water tank before exiting the filtration system for further processing or use. The filtration media may be birm, greensand or similar material. Birm media is typically used for removing iron and manganese. If sulphur levels in the water are very high, then greensand is often used as it can filter out iron and manganese and in addition is more effective for filtration of the sulphur. The filtration media serves to capture the contaminants thereby to filter the water. In time, as more and more filtered water is produced, the continued filtration leads to a condition in which there is a high concentration of contaminants in the filtration media, such that further incoming water will not undergo effective filtration. As such, the filtration media must be regenerated.
During regeneration the control system exits service mode and enters regeneration mode. This typically involves backwashing the water tank with source water to unsettle and push up the filtration media to dislodge captured contaminants and carry the captured contaminants from the water tank and out of the water filtration system and down a drain. After this operation, the filtration system having regenerated the treatment media can re-enter service mode.
Other water treatment systems are available for use alone or in addition to a filtration system for disinfecting water by removing organisms such as bacteria from the water before it is used. For example, it is known to bring ozone gas into contact with the water to be disinfected. Ozone gas can be very effective at killing waterborne organisms.
Ozone gas treatment systems may employ electric air pumps for injecting ozone gas into the water to be disinfected. Such ozone gas treatment systems are expensive and complex, and further require regular specialized servicing in order to continue to work effectively. Alternative systems employ water restricting devices to create suction in a line for suctioning ozone gas, using water pressure from a water supply pump. However, problems with effective suction of ozone gas arise when the water supply pump cannot produce a suitable amount of water pressure to accordingly produce a suitable amount of suction. Additional complex devices are also installed on a water tank to removing excess ozone gas from the water.